London officials have some advice for truck drivers during the Olympics: Lay off the horns.

Transport for London issued a code of conduct Monday for delivery drivers who will be working late at night and in the wee morning hours to deliver supplies during the 2012 London Olympics.

The code urges drivers not to whistle to get the attention of store employees receiving their goods. Alarms and horn honking are also frowned upon.

The guidelines are part of a wider effort by London transport officials to keep deliveries on track as the city handles nearly an extra million visitors for the Olympics. Delivery times are being shifted to avoid the heavy daytime traffic expected during the games, which run from July 27-Aug. 12.